If a person can find the advantages of his opponent, it will bring him immeasurable benefits, because it will definitely make him surpass his opponent. -Goethe

If you go in, you can't get home, but if you go out, you will be invincible against foreign invasion, and the country will perish forever-Mencius

A real opponent will instill a lot of courage in you (Kafka)

Wise men get more from their enemies than fools get from their friends (Gracian)

The enemy's view of us is closer to the truth than our view of ourselves (France)

Not everyone can be a friend, but anyone can be an enemy (Europe)

Equally dangerous to you are: your friend's enemy, your enemy's friend (Arabia)

There is no stronger foundation for friendship than having a common enemy (Ireland)

Those who are strictly neutral between us and the enemy seem to be closer to the enemy (Fu Shang)

The flame should be doused with cold water; The enemy (Mongolia) should be conquered by force.